The invention concerns a combustion motor having a combustion chamber for the combustion of the working gas during communication with combustion chamber. The pump chamber can be an explosion phase and a pump chamber which is in communication with combustion chamber. The pump chamber can be filled with a drive fluid by way of an inlet opening, and then can have the drive fluid expelled out of an outlet opening under the action of the combustion gas formed during the explosion phase.
A combustion motor of this kind is known for example from Swiss patent specification No 450 946 and is referred to therein as a reaction motor which can be used for example for driving water craft. In such motors the fluid in the pump chamber represents a kind of a fluid piston which is to be expelled as a whole from the pump chamber by the pressure of the combustion gas.
The known combustion motors of this kind suffer from the disadvantages inter alia of the relatively low level of efficiency of the machine and the low numbers of phases which can be achieved.